British-Australian woman Kylie Moore-Gilbert is despairing at her isolation inside Tehran’s Evin prison, believing she has been abandoned to her decade-long sentence, according to sources within the prison.

Political prisoner Moore-Gilbert, who has spent more than 600 days inside the notorious Ward 2A of Tehran’s Evin prison, much of it in solitary confinement, was convicted in a secret trial and sentenced to 10 years prison on charges of espionage.

No evidence has ever been presented of her alleged crimes, and the Australian government rejects them as baseless and politically motivated.

The Australian embassy in Tehran is maintaining some contact with Moore-Gilbert. Australia’s ambassador Lyndall Sachs last spoke to her on 21 April. She has also spoken with her family.

Nasrin Sotoudeh – a prominent Iranian human rights lawyer who has most famously represented opposition activists, prisoners sentenced to death for underaged crimes, and women arrested for not wearing a hijab in public – is also in Evin prison.

Her husband, rights campaigner Reza Khandan – who has also previously been jailed in Evin – said information from inside the prison said Moore-Gilbert had been held for long periods in solitary confinement in a 2m by 3m cell, and blindfolded if she was moved around the prison.

When allowed to speak with other prisoners, Moore-Gilbert had reportedly said she believed she had been abandoned by the Australian government.

“Since her arrest, [Moore-Gilbert] has been held in horrific and unbearable conditions in the security detention center and is not allowed to communicate with other prisoners,” he posted online.

“She, unlike other prisoners, was denied the opportunity to receive money and buy from a prison store, and her letters of complaint were prevented from being sent.

“She is outraged by the Australian government and embassy in Iran for neglecting her continued detention and intolerable circumstances.”

It is known Moore-Gilbert has undertaken numerous hunger strikes in protest at her conditions. Khandan said Moore-Gilbert had attempted suicide multiple times but this has not been independently verified, and has been rejected by some sources with knowledge of her conditions.

The executive director of the Centre for Human Rights in Iran, Hadi Ghaemi, said the Australian government needed to forcefully demand her release.

“Kylie’s cries for help are so loud and desperate that even the walls of one of Iran’s most notorious prisons can’t silence them,” he said.

Under Iranian law, once a prisoner’s trial, sentencing and appeals are complete, they should be moved into the general section of the prison, not the secretive Ward 2A, run by the hardline Revolutionary Guards.

“Iranian intelligence agents are trying to muzzle Kylie by unlawfully isolating her in a severely restricted ward that’s supposed to be used for temporary detention for more than a year,” said Ghaemi. “And no Iranian official has explained why.”

“We’re very concerned by the particularly cruel way she’s being treated and barred from having contact with almost everyone,” he added. “It’s as though her captors are trying to prevent her from revealing information that could implicate them.”

Moore-Gilbert has been publicly silent for months, since a series of smuggled letters were published earlier this year detailing the privations of her imprisonment, including months isolated in solitary confinement, and a shortage of food, medicine, and money to buy personal items.

“I am not a spy. I have never been a spy and I have no interest in working for a spying organisation in any country. When I leave Iran, I want to be a free woman and live a free life, not under the shadow of extortion and threats.”

While Iran has furloughed more than 100,000 prisoners out of concern Covid-19 could sweep through the country’s overcrowded prisons, Moore-Gilbert has not been among those released.

The Australian government has insisted on pursuing a strategy of quiet diplomacy with Tehran and has rarely commented publicly on Moore-Gilbert’s case.

A spokesman for the department of foreign affairs and trade told the Guardian Moore-Gilbert’s health and well-being were high priorities for the government, which was continuing to “advocate strongly” to ensure she was treated humanely and in accordance with international standards.

“The Australian embassy in Tehran continues to impress on Iranian authorities the importance of Dr Moore-Gilbert’s maintaining regular contact with her family and consular officials in Tehran.”

The foreign minister, Marise Payne, has raised the issue in meetings with the Iranian foreign minister, Javad Zarif, but there is a sense, from observers of Iran’s domestic politics, that Zarif has little influence in determining the actions of the Revolutionary Guards who hold Moore-Gilbert.

Australia has said it does not engage in prisoner swaps, but it has – at least indirectly – been involved in apparent swaps recently.

Two Australian travel bloggers, Mark Firkin and Jolie King (who is also a British citizen), were released from Evin prison in October after being arrested in July, reportedly for flying a drone over a military installation.

They were released just after University of Queensland doctoral research student, Iranian national Reza Dehbashi Kivi, was released from a Brisbane jail after 13 months held facing sanctions-busting allegations, and a demand from the US he be extradited there to face court.

Moore-Gilbert, a graduate of Melbourne and Cambridge universities, is a lecturer in Islamic studies at the University of Melbourne.

She was arrested in September 2018 after attending an academic conference, at which she was invited to speak, in Qom. Fellow conference delegates and an interview subject for her academic work flagged her as “suspicious” to Iran’s Revolutionary Guards, who arrested her at Tehran airport.

No evidence has ever been presented publicly that Moore-Gilbert was involved in espionage and the Australian government says it rejects her conviction.